IE: error on page.

I’m testing my new BBPress installation; I created a second – “normal” – user account for me, and am posting things to test everything. I noticed that, in Firefox, so far so good. However, I noticed something in IE: when I am not logged in, everything loads fine. But once I’m logged in (as a “normal” member), and navigate to various threads, the page loads, but with “errors” (as seen at the bottom of IE’s status bar). The CSS seems to mess up slightly, but otherwise everything loads correctly.

If I click on the report, it says that the “object doesn’t support this property or method”, on line 56, character 2.